Philippine Vice-President Sara Duterte-Carpio has recently adopted a more assertive stance on the South China Sea, urging the armed forces to defend sovereignty without directly challenging Beijing.

Philippine Vice-President Sara Duterte-Carpio has twice in recent weeks urged the country’s armed forces to defend its sovereignty, in a carefully calibrated attempt to sound more assertive on the South China Sea issue without directly challenging Beijing, according to analysts. While Duterte-Carpio did not name China, her repeated calls marked a tonal shift from her earlier approach, when she either avoided the issue or warned against letting it define Manila’s broader relationship with...